Upgraded to version 28 of mojo-parent, and added gpg-plugin.
Upgraded to version 28 of mojo-parent, and added gpg-plugin.

git-svn-id: 65278d6cf7ed3f925d5aaa21cb5f6410da7c440d@13694 52ab4f32-60fc-0310-b215-8acea882cd1b

mojohaus/castor-maven-plugin